MANNITOL 15%
Clinical safety rating
safeOther diuretics may have additive effects Can cause fluid and electrolyte imbalances and pulmonary congestion.
Increases plasma osmolality, drawing water from intracellular and interstitial spaces into the vascular compartment, thereby reducing intracranial pressure and intraocular pressure. Acts as an osmotic diuretic in the kidneys, increasing urine flow by inhibiting water reabsorption in the proximal tubule and loop of Henle.
| Metabolism | Mannitol is not significantly metabolized; it is primarily excreted unchanged by the kidneys via glomerular filtration. |
| Excretion | Primarily renal (90-100% as unchanged drug); negligible biliary/fecal elimination. |
| Half-life | Terminal elimination half-life approximately 0.25-1.5 hours in normal renal function; prolonged to 24-36 hours in renal impairment. |
| Protein binding | Approximately 0-10% bound to plasma proteins (negligible binding). |
| Volume of Distribution | 0.5-0.8 L/kg; primarily distributes in extracellular fluid (interstitial space). |
| Bioavailability | Intravenous: 100% (only route used therapeutically); not administered orally due to minimal absorption (oral bioavailability < 5%). |
| Onset of Action | Intravenous: osmotic diuresis begins within 1-3 minutes; peak effect in 30-60 minutes. Intracranial pressure reduction occurs within 15-30 minutes. |
| Duration of Action | Diuretic effect lasts 1-3 hours after IV infusion; intracranial pressure reduction persists for 2-6 hours depending on dose and renal function. |
| Molecular Weight | 182.17 |
1-2 g/kg as a 15% solution intravenously over 30-60 minutes. Typical adult dose: 100-200 g (667-1333 mL of 15% solution) administered as a single dose for reduction of intracranial pressure or promotion of diuresis.
| Dosage form | INJECTABLE |
| Renal impairment | Contraindicated in anuria due to severe renal disease. For GFR <50 mL/min, use with caution and monitor serum osmolarity and renal function. No specific dose reduction defined; consider alternative therapy if GFR <20 mL/min. |
| Liver impairment | No specific adjustment for Child-Pugh class. Use with caution in ascites or severe hepatic impairment due to risk of volume overload and electrolyte disturbances. |
| Pediatric use | 0.25-1 g/kg (1.67-6.67 mL/kg of 15% solution) intravenously over 30-60 minutes. Repeat doses as needed based on clinical response, up to 1-2 g/kg. |
| Geriatric use | Initiate with lower doses (e.g., 0.5 g/kg) and titrate carefully due to increased risk of volume overload, electrolyte imbalance, and renal impairment. Monitor renal function, serum osmolarity, and fluid status closely. |
| 1st trimester | Mannitol is categorized as FDA pregnancy category C. Animal reproduction studies have not been conducted. Use only if clearly needed and potential benefits outweigh risks. Osmotic diuresis may cause maternal hypotension and electrolyte imbalance, potentially affecting placental perfusion. |
| 2nd trimester | Limited data; same considerations as first trimester. Monitor maternal fluid and electrolyte status closely. Avoid in conditions like preeclampsia where osmotic shifts may be harmful. |
| 3rd trimester | Use with caution near term; osmotic agents can cross placenta and may cause fetal hyperosmolality, dehydration, and electrolyte disturbances. Risk of neonatal fluid and electrolyte imbalance. |
Clinical note
Other diuretics may have additive effects Can cause fluid and electrolyte imbalances and pulmonary congestion.
| FDA category | Animal |
| Placental transfer | Mannitol is a small, osmotically active molecule that can cross the placenta. Studies indicate significant transfer with fetal levels approaching maternal levels. It is used therapeutically to reduce brain edema in neonates, confirming placental passage. |
| Breastfeeding | It is unknown whether mannitol is excreted in human milk. Due to its high molecular weight and low lipophilicity, significant transfer is unlikely. Caution is advised; consider benefit versus risk. Monitor infant for signs of diarrhea or electrolyte disturbance if mother receives high doses. |
| Lactation Rating | L3 (Moderately Safe) |
| Teratogenic Risk | Mannitol is a category C drug. First trimester: No well-controlled studies, but animal studies have not shown teratogenic effects; risk cannot be excluded. Second and third trimesters: Use only if clearly needed, as osmotic diuresis may cause fetal dehydration, electrolyte imbalances, or altered placental blood flow. There is no evidence of direct teratogenicity. |
| Fetal Monitoring | Monitor maternal fluid balance, serum electrolytes (sodium, potassium, chloride), osmolality, and renal function. Assess urine output hourly during infusion. Fetal monitoring (heart rate tracings) is recommended, especially in setting of maternal fluid shifts or if used for elevated intracranial pressure in pregnancy. |
| Fertility Effects | No human studies on fertility. Animal studies have not shown impaired fertility at therapeutic doses. Mannitol is an osmotic diuretic and does not directly affect gonadotropic hormones or gametogenesis. Use during pregnancy does not appear to affect future fertility. |
■ FDA Black Box Warning
None
| Common Effects | edema |
| Serious Effects |
Anuria due to severe renal diseasePulmonary congestion or frank pulmonary edemaActive intracranial bleeding (except during craniotomy)Severe dehydrationHypersensitivity to mannitol or any componentPatients with established acute tubular necrosis on dialysis
| Precautions | May cause volume expansion, pulmonary congestion, or heart failure in patients with cardiac dysfunction. Monitor serum electrolytes, osmolality, and renal function. Use with caution in patients with renal impairment, as accumulation can cause metabolic acidosis. Risk of osmotic nephrosis or acute kidney injury with high doses or prolonged use. May exacerbate intracranial hemorrhage due to increased cerebral blood volume. |
| Food/Dietary | No significant food interactions. Avoid excessive sodium intake to prevent fluid retention. |
| Clinical Pearls | Monitor serum osmolality and electrolyte levels closely during therapy; use in cerebral edema requires maintaining serum osmolality 310-320 mOsm/L. Administer via in-line filter (0.22 micron) to prevent crystal emboli. Rapid infusion may cause transient hypervolemia; caution in heart failure or renal impairment. Onset of diuresis is 1-3 hours after IV administration. |
| Patient Advice | This medication increases urine output to reduce fluid buildup. · Report any chest pain, difficulty breathing, or swelling in ankles/feet. · You may experience headache, nausea, or dry mouth. · Avoid excessive salt intake to prevent fluid retention. · Notify your doctor if you have kidney disease or heart conditions. |
Loading safety data…